FracFocus, a reporting system where oil and gas operators can publicly disclose information about chemicals used in the hydraulic fracturing process, is frequently marketed as a tool for promoting transparency in the fracking industry.

Key Findings
Analysis by Gary Allison and Vivian Underhill shows FracFocus has limited utility as a comprehensive data gathering tool, as evidenced by significant gaps in its disclosures, including masked trade secrets, ambiguous data, and omissions.
With over 1,300 chemicals identified and many more going unreported, there is an urgent need for access to complete and transparent data so appropriate action can be taken in response to information revealed in the disclosures.
This analysis reveals how comprehensive regulatory and reporting reforms are imperative to closing holes in FracFocus data and holding the oil and gas industry accountable for its impacts.
Overview
FracFocus, the national registry of chemical uses in fracking, can give the impression of a highly detailed and complete record. In reality, disclosures provided by fracking operators are plagued with significant holes. As we look to understand potential health and environmental consequences of fracking, we must come to grips with masked reports and omissions from a full disclosure. These include trade secrets and ambiguous data as well as reporting based on abbreviated lists. This lack of transparency makes it difficult to fully assess the true risks associated with fracking. Although FracFocus is an important window into the industry’s use of fracking chemicals, we must remember that it is far from a complete view.
Transparency
With Pennsylvania’s DEP collaboration with the gas producer CNX and that company’s claim of “Radical Transparency,” the disclosure of fracking chemicals has recently re-entered the public eye. The use of hazardous chemicals during oil and gas extraction has long been a contentious issue. [1] Further, the simple reporting of those materials is one of the few windows into a process that has been shown to have negative impacts on human and environmental health. While the fracking phase of a well isn’t the only time in which hazardous chemicals are employed, it is one of the better documented phases.
Central to that documentation is the so-called “national hydraulic fracturing chemical disclosure registry,” FracFocus, which is one of the biggest publicly available data sources of fracking chemical uses in the world. It is cited by the fossil fuel industry as an example of its transparency and good stewardship. It covers over a decade of on-shore fracking operations in most of the US states where fracking is active. This period includes a large part of the fracking boom that made the US a dominant oil and gas producer. FracFocus includes millions of chemical records in over 200,000 disclosures.
If the point of the public access to chemical data is to help us understand the health and environmental consequences of the industry, we must ask: How complete is FracFocus data for this goal? Understanding of risks can only be assessed with full and detailed data. Lists of chemicals in the Clean Water Act and Safe Drinking Water Act depend on well-defined and very specific chemical identification. [2]
For this report, we use data from the Open-FF project, a FracTracker-sponsored project that organizes and cleans FracFocus data to make it more accessible and research-friendly. Combining this data and our FracFocus analysis experiences, we categorize the types of omissions and masking mechanisms that are baked into the FracFocus disclosure instrument. For this purpose, we use data downloaded from FracFocus on Feb 17, 2024. This data largely reflects 2014 through 2023 because earlier FracFocus data is not available for bulk download.
A Naive Expectation
One might reasonably expect that a chemical disclosure instrument like FracFocus would document all the chemicals used in a fracking operation, and in a manner useful to the public. For example, if an Operator publishes a list of chemicals pumped into the ground 1,000 feet from an elementary school, like the six wells on a well pad in Tarrant County, Texas, we could expect the identity and quantity of the chemicals to be clearly stated. We might expect something like the figure below, where what goes into the ground during fracking is directly represented in the FracFocus disclosure.
Indeed, the detailed nature of individual FracFocus disclosures can give the impression of a complete record. If you look at the six disclosures [3] for that Texas well pad at the FracFocus site, you will find dozens of chemicals used during the fracking process. But clearly, if any chemicals are left out of disclosures, our ability to understand fracking impacts is handicapped.
Visible Holes
Once one begins examining FracFocus disclosures, the most obvious blow to that naive expectation is the long list of masked chemical records. Two major categories are Trade Secret designations and ambiguous records.
Trade Secrets
The biggest class of these masked chemicals are the “proprietary claims,” “trade secrets,” and “confidential business information” in which the company reports the use of a chemical but hides its identity. [4] These designations are allowed by many state and federal regulators. These masked chemicals are widespread: most disclosures report at least one record that is a proprietary designation, as illustrated in the figure. Between 2014 and 2022, over 10 billion pounds of these masked chemicals were used.
Here is an example of trade secret records: the figure below is an excerpt of the disclosure for the Texas well 42-227-40269-00-00 by Diamondback E&P in August 2022 with the proprietary records marked with red.
The FracFocus website asserts that proprietary records include the functional class of the chemical as shown in most records in the example above. In a recent analysis, we found that along with proprietary chemicals identified by a given functional group, other chemicals in that group were often dominated by materials on Clean Water Act and Safe Drinking Water Act lists. [5] But even given a functional group, the lack of specific identification prevents us from understanding the actual risk of the chemical simply because reported functional groups span a wide variety of materials. Further compounding the issue, tens of thousands of records offer no functional group information, labeled solely as “proprietary,” “trade secret,” “surfactant,” or are simply unlabeled.
The percent of all FracFocus chemical records that are designated “proprietary” is 15%. [6] There are over 800,000 proprietary records. For more details into this set of records, see the proprietary detail page of Open-FF.
Propriety FracFocus records
For more details into this set of records, see the proprietary detail page of Open-FF.
Proprietary FracFocus records
Ambiguous Data
Like proprietary claims, the records in this next group still appear in disclosures but they are simply not labeled or are labeled in a way that cannot be resolved to a single, specific chemical. That is, while they appear in the disclosure, companies do not give us enough information to understand their identity and therefore their toxicity.
For example, there are over 50,000 records with a recorded quantity but with no CASNumber given. Among these records, over 5,000 represent the carrier of the disclosure. In those disclosures, while the name implies some mix of water and other ingredients, there is no hint what those other ingredients might be. The mass of those records is at least 180,000,000,000 pounds. Other ambiguous identification includes CAS codes that are either obvious dummy codes (e.g., ‘0000-00-0’ or ‘xxxx-xx-x’) or codes for chemicals that are clearly wrong. [7]
When we cannot resolve these records at Open-FF, we label them as “ambiguousID.” For more details into this set of records, see the ambiguousID detail page.
So, unlike the naïve expectation, there are clearly holes in the disclosure that we can see:
Invisible Holes
We saw above that Proprietary and Ambiguous classes are unidentified chemicals but we can see that they have been used. Another set of chemicals are injected in fracking operations that are not mentioned in FracFocus disclosures. We know they exist from evidence outside of FracFocus data. Included here are three classes that we know of: Safety Data Sheet omissions, water sources that contain more than water, and distillates.
Partial Ingredients List
Much of the chemical information in FracFocus is based on products’ Safety Data Sheets (SDS, sometimes called MSDS) that are compiled to comply with OSHA regulations. These documents, summarized here by OSHA, are primarily developed to inform workers who must work with these materials and to aid emergency response teams that might have to deal with spills or injuries. They are typically 3-15 pages and are usually found as PDF files. (Click here for a quick example. Note that the format of SDS/MSDS has changed in the last decade; section numbers may be different than the current format.)
FracFocus and the companies submitting chemical disclosures have re-purposed Safety Data Sheets from their worker safety/emergency responder origins to serve as an ingredient list for disclosures by using the SDS section that outlines the composition of the product. Because manufacturers of these products were already required to generate these SDS for each product, the SDS apparently became a handy source of ingredients for public disclosure. Below is the reported ingredient list from an example SDS for Plexsurf 251E by Chemplex:
Note here that there are three hazardous ingredients listed and that their CAS numbers are listed. The percent listed is also required but may be given as a range to allow the manufacturer to mask exact recipes or to allow for variability in the manufacturing process. FracFocus instructions stipulate that the upper level of the range should be used in their disclosures.
Clearly, this is an abridged list of what is in the product. At most, these three ingredients comprise 46% of the mass in the product, but as little as 32%. What is in that other 54-68% of the product? Often, only the manufacturer knows. Even operating companies, while they are responsible for the completeness of the disclosure, may never know all ingredients of the products they use (Horwitt & Teklemichael 2022).
Are these non-disclosed chemicals a problem? The SDS is not designed to be an exhaustive ingredient list unless all components are considered “hazardous.” Although it is possible that the non-identified percentage is benign, there are reasons to be suspicious of the absence. First, what may be considered non-hazardous in an occupational, or “intended use” setting (the main purpose of an SDS) may be problematic from an environmental perspective. Second, what is considered hazardous can change over time. For example, the status of PFAS chemicals has recently changed dramatically in the US. Third, while manufacturers are responsible for the SDS, they are also given significant leeway in declaring what is “hazardous” in their products and therefore visible in FracFocus disclosures.
Considering that PFAS surfactants have been mentioned in multiple places as highly effective in fracking (see Horwitt & Gottlieb, 2022), and yet rarely appear in FracFocus, it is reasonable to be suspicious that they may be used either as inert ingredients, deemed to be non-hazardous or hidden as proprietary ingredients. Because operators probably do not have full access to ingredient lists, the only way to verify that products are free of chemicals like PFAS may be analytical tests by independent labs.
Is the Carrier Really Just Water?
In the vast majority of fracking disclosures, water is the primary carrier of sand and other ingredients. This water often comprises 80% or more of the whole fracking fluid.
The source of that water may be nearby rivers, streams or lakes, from groundwater wells or even from municipal sources. And while the chemical identity reported in FracFocus for the vast majority of disclosures is simply “water” (CASRN: 7732-18-5), there is a disclaimer at the bottom of PDF disclosures that:
“Total Water Volume sources may include fresh water, produced water, and/or recycled water.”
This disclaimer reflects the reality that the wastewater generated by oil and gas extraction is often reused by operators. The volume of this “produced water” can be many times the volume of the oil or gas produced and is a nuisance by-product of the industry. This water can include “flow-back” materials from the original fracking slug. While this produced water has been used extensively in “enhanced oil recovery,” much of it is disposed of in waste injection wells. In recent years there has been a push to increase its use as part of the fracking carrier in newer wells.
The actual composition of produced water is hard to quantify. Analysis of produced water is expensive and usually only tests for common markers such as mineral elements and known toxic materials (like “BTEX”, benzene, toluene, ethylbenzene and xylenes). Targeted analysis for other specific molecules such as PFAS chemicals is rarely performed and, because it is targeted, can still overlook materials that are important but not on the analyte list.
Nevertheless, when analysis of produced water is performed, it is common to find a toxic cocktail (see Stringfellow and Camarillo, 2019; Neff et. al, 2011; Leuk & Gonsior, 2017. And see the EPA list from Danworth et al.), usually a combination of “natural” materials, such as hydrocarbons, radionuclides, and heavy metals as well as flow-back materials from fracking additives and the chemicals formed under the high pressure and temperature of the fracking process.
Therefore, produced water is much more than just water. However, even in FracFocus disclosures that explicitly report the use of produced water, the composition is typically just reported as water alone. For contrast,in one revealing set of about 120 FracFocus disclosures in 2018-19 in Texas, a few other materials are included as ingredients of produced water, most notably benzene at a concentration of 0.1% of the produced water. Because of the large volume of produced water used in these fracks, the quantity of benzene used in most of these wells was over 50,000 lbs. But for produced water, this reporting of more than just a water record is the exception, not the rule.
The bottom line is that the companies may be using water sources that include hazardous chemicals, and because these water volumes may be huge, the quantity of the hazardous hitchhikers will be very large as well. However, it is typical for none of that to make it into the disclosure.
What’s Hiding in That Mixture?
As mentioned in the introduction, to understand the risks associated with fracking chemicals, it is necessary to have a complete and well-defined list of materials. When a research paper is published that finds the toxicity of, say, naphthalene, researchers are reluctant to apply those results to other materials, even if it is closely related, simply because toxicity can be highly dependent on specific molecular characteristics.
That need for a highly specific identity is a big obstacle with the next invisible “hole” in FracFocus. This third group consists of materials labeled by the Toxic Substance Control Act as “unknown or variable composition, complex reaction products or biological materials” (UVCBs). Within fracking operations, many UVCBs are petroleum distillates.
For distillates, the unknown and variable part of their composition begins with the source material: crude oil is itself a UVCB and can contain hundreds of thousands of distinct chemicals. The distillation process is able to separate different groups of materials based on their chemical properties such as volatility. But these fractions are often approximate because of huge variation in the source material, the specific conditions during the distillation process and variability across refineries. (See Lai et al., 2022)
How Common Are UVCBs in FracFocus?
UVCBs form a large group of materials in FracFocus disclosures: more than 300 materials are UVCBs, that is, 20% of all identified chemicals. Furthermore, among all additives (that is, ignoring water and sand), we find that UVCBs account for 15% of the mass across FracFocus. [10]
Considering a Single UVCB in FracFocus:
The difficulty with UVCB for users of FracFocus is that, while they are mixtures of many (often toxic) chemicals, they are represented by a single CAS number that obscures the component chemicals in the mixture. A common FracFocus material, “Heavy aromatic solvent naphtha (petroleum),” is identified by a single CAS number: ‘64742-94-5’. As its name suggests, it has a high percentage of aromatic compounds; that is, 64742-94-5 is designed to be heavily laden with chemicals like naphthalene, a chemical on the Safe Drinking Water Act list. But because it is a UVCB, the precise mixture is unknown or variable and therefore not reported.
We can get a glimpse into the most abundant components of these UCVBs because some Safety Data Sheets for the UVCBs list those constituents. For example, the ExxonMobil’s SDS for their product “Solvent Naphtha H” is 100% 64742-94-5, but it also lists some components:
Another maker of a 100% 64742-94-5 product, Monument Chemical, provides this list:
Safety Data Sheets from other companies for products reported as 100% 64742-94-5 either list no component chemicals or deviations from these lists (for example, see Shell’s product.)
It is worth noting that many of the chemicals in these SDS are never reported directly in FracFocus. Remember, this product is a solvent and therefore designed to be composed of aromatics. In fact, Exxon’s product description sheet reports at least 98% aromatic content, even though Exxon’s three SDS components account for, at most, a little more than 50% of the whole mixture. Although we cannot know for sure, whenever 64742-94-5 is used, a significant portion of its mass is likely composed of these aromatics but they are hidden by the UVCB CAS number.
We can start to see what might be missing from UVCB labeling if we make the simple assumption that the Exxon SDS is representative of the 64742-94-5 used across FracFocus. That is, for every use of 64742-94-5, naphthalene comprises 0 to 14% of its mass. Considering that the currently reported mass of 64742-94-5 used is 69,100,000 pounds, we find that the amount that this one distillate adds to the directly reported mass of its chemical components is substantial:
Component | Percentage of 64742-94-5
(from Exxon SDS) |
Mass directly reported across FracFocus | Additional mass as a component of 64742-94-5 |
naphthalene | 0-14% | 12,700,000 lbs. | 0 to 9,680,000 lbs. |
1-methylnaphthalene | 0-12.5% | 0 lbs. | 0 to 8,640,000 lbs. |
2-methylnaphthalene | 0-26% | 0 lbs. | 0 to 18,000,000 lbs. |
Like produced water, it is difficult to directly identify the components of UVCB chemicals. The labels they are given identify rough characteristics but don’t reveal the details we need to assess environmental and health risks.
Conclusion
There is no doubt that FracFocus, as it exists now, is more useful to the public than no disclosure at all. From it, we have learned that hazardous chemicals regulated in other industries are commonly used in large quantities throughout the fracking industry without the same oversight. We’ve seen that despite the contentious nature of the use of trade secret chemicals, the practice continues to increase. We’ve learned that the number of chemicals used in fracking is over 1,300, many of which are virtually unstudied for their environmental and health effects, and the list continues to grow. And we can use FracFocus to examine some of the important chemicals used near specific sites, like homes or schools.
In spite of that, much of what the industry injects remains murky to the public because of the holes that exist in FracFocus. Those of us looking to understand potential health and environmental consequences of fracking must come to grips with these partial disclosures. And we should be suspicious of disclosure “improvements” that don’t address these gaping holes.
Endnotes
[1] For example, see Avidan, Etzion and Gehman, 2019, Concerned Health Professionals of NY, 2023, and Kinchy & Schaffer, 2018.
[2] While these and other federal environmental laws are important safeguards, we should note that the fracking industry is largely exempt from them. Nevertheless the lists are useful signposts about the dangers of specific chemicals.
[3] To view those disclosures, click on the following links, then click on the “PDF Disclosure Form” button below the map: 42-439-34340, 42-439-34911, 42-439-37149, 42-439-37150, 42-439-37151, 42-439-37152; Note that in these FracFocus disclosures, quantity is only given as relative to the entire fracking liquid (% HF Fluid). This obscures the absolute quantity, that is, the weight. Users must either dig into the bulk data download or use Open-FF to access these weights.
[4] OpenFF uses the `CASNumber` and `IngredientName` fields of FracFocus as indicators of explicit proprietary designations to lump all these labels together and facilitate a more coherent picture of these records. The CASNumber is supposed to be the Chemical Abstract Service’s registration number, an authoritative way to identify chemicals.
[5] See Table 3 of Underhill et al. 2024.
[6] While individual disclosures typically hide somewhere between 0 and 40% of records as trade secrets, remarkably, there are some that hide much more. Two recent disclosures from New Mexico only identify water and sand (click on the API number to view the FracFocus disclosure: 30025513920000 and 30025491370000). In 2019, the operator, Laramie Energy published over 25 disclosures in which water was the only non-proprietary record. Here’s an example.
[7] For example, five disclosures report the proppant of the fracking job as ‘50-28-2‘ but that chemical is estradiol, the human female hormone. Because this code is not typographically close to any FracFocus chemicals, this is likely not a mistake, but a stupid prank.
[8] Because operators are trying to find new uses for produced water, it may be processed or “recycled.” The degree to which the contaminants are removed for the produced water during the recycling process is dependent on the effectiveness of the treatment and the expected use for the recycled water (e.g. agricultural vs. fracking fluid). Little data is available about that product stream back into the well.
[9] FracFocus has recently added an optional component for operators to report the source of water used. While “produced water” is one of the categories reported, early uses of this option has not added much more information to the chemical composition of those disclosures using produced water.
[10] Type “UVCB” into the search bar of the Chemical Index to browse all UVCBs that have been reported in FracFocus
References
[1] Avidan, Miron, Dror Etzion, and Joel Gehman. “Opaque Transparency: How Material Affordances Shape Intermediary Work.” Regulation & Governance 13, no. 2 (2019): 197–219. https://doi.org/10.1111/rego.12217.
[2] Concerned Health Professionals of NY. “Compendium of Scientific, Medical, and Media Findings Demonstrating Risks and Harms of Fracking and Associated Gas and Oil Infrastructure, Ninth Edition, October 19, 2023,” https://concernedhealthny.org/compendium/.
[3] Danforth, Cloelle, Weihsueh A. Chiu, Ivan Rusyn, Kim Schultz, Ashley Bolden, Carol Kwiatkowski, and Elena Craft. “An Integrative Method for Identification and Prioritization of Constituents of Concern in Produced Water from Onshore Oil and Gas Extraction.” Environment International 134 (January 1, 2020): 105280. https://doi.org/10.1016/j.envint.2019.105280.
[4] Horwitt, Dusty, Barbara Gottleib. “Fracking with ‘Forever Chemicals’ in Colorado | Physicians for Social Responsibility,” January 31, 2022. https://psr.org/resources/fracking-with-forever-chemicals-in-colorado/.
[5] Horwitt, Dusty, Meilen Teklemichael, “Chemical Makers’ Exemptions from Fracking Chemical Disclosure Rules | Physicians for Social Responsibility,” July 12, 2022. https://psr.org/resources/chemical-makers-exemptions-from-fracking-chemical-disclosure-rules/.
[6] Kinchy, Abby, and Guy Schaffer. “Disclosure Conflicts: Crude Oil Trains, Fracking Chemicals, and the Politics of Transparency.” Science, Technology, & Human Values 43, no. 6 (November 1, 2018): 1011–38. https://doi.org/10.1177/0162243918768024.
[7] Lai, Adelene, Alex M. Clark, Beate I. Escher, Marc Fernandez, Leah R. McEwen, Zhenyu Tian, Zhanyun Wang, and Emma L. Schymanski. “The Next Frontier of Environmental Unknowns: Substances of Unknown or Variable Composition, Complex Reaction Products, or Biological Materials (UVCBs).” Environmental Science & Technology 56, no. 12 (June 21, 2022): 7448–66. https://doi.org/10.1021/acs.est.2c00321.
[8] Underhill, Vivian, Gary Allison, Holden Huntzinger, Cole Mason, Abigail Noreck, Emi Suyama, Lourdes Vera, and Sara Wylie. “Increases in Trade Secret Designations in Hydraulic Fracturing Fluids and Their Potential Implications for Environmental Health and Water Quality.” Journal of Environmental Management 351 (February 1, 2024): 119611. https://doi.org/10.1016/j.jenvman.2023.119611.
[9] Underhill, Vivian, Angelica Fiuza, Gary Allison, Grace Poudrier, Sarah Lerman-Sinkoff, Lourdes Vera, and Sara Wylie. “Outcomes of the Halliburton Loophole: Chemicals Regulated by the Safe Drinking Water Act in US Fracking Disclosures, 2014–2021.” Environmental Pollution 322 (April 1, 2023): 120552. https://doi.org/10.1016/j.envpol.2022.120552.
Join the Conversation
Stay Informed
Support Our Work
FracTracker Alliance helps communicate the risks of oil and gas and petrochemical development to advance just energy alternatives that protect public health, natural resources, and the climate.
By contributing to FracTracker, you are helping to make tangible changes, such as decreasing the number of oil and gas wells in the US, protecting the public from toxic and radioactive chemicals, and stopping petrochemical expansion into vulnerable communities.
Your donations help fund the sourcing and analysis of new data so that we can keep you informed and continually update our resources.
Please donate to FracTracker today as a way to advocate for clean water, clean air, and healthy communities.
Leave a Reply
Want to join the discussion?Feel free to contribute!